28.3.45 INFORMATION_SCHEMA USER_ATTRIBUTES 表
The USER_ATTRIBUTES
table provides information about user comments and user attributes. It takes its values from the mysql.user
system table.
The USER_ATTRIBUTES
table has these columns:
-
USER
The user name portion of the account to which the
ATTRIBUTE
column value applies. -
HOST
The host name portion of the account to which the
ATTRIBUTE
column value applies. -
ATTRIBUTE
The user comment, user attribute, or both belonging to the account specified by the
USER
andHOST
columns. The value is in JSON object notation. Attributes are shown exactly as set usingCREATE USER
andALTER USER
statements withATTRIBUTE
orCOMMENT
options. A comment is shown as a key-value pair havingcomment
as the key. For additional information and examples, see CREATE USER Comment and Attribute Options.
-
USER_ATTRIBUTES
is a nonstandardINFORMATION_SCHEMA
table. -
To obtain only the user comment for a given user as an unquoted string, you can employ a query such as this one:
mysql> SELECT ATTRIBUTE->>"$.comment" AS Comment -> FROM INFORMATION_SCHEMA.USER_ATTRIBUTES -> WHERE USER='bill' AND HOST='localhost'; +-----------+ | Comment | +-----------+ | A comment | +-----------+
Similarly, you can obtain the unquoted value for a given user attribute using its key.
-
USER_ATTRIBUTES
contents are accessible as follows:-
All rows are accessible if:
-
The current thread is a replica thread.
-
The access control system has not been initialized (for example, the server was started with the
--skip-grant-tables
option). -
The currently authenticated account has the
UPDATE
orSELECT
privilege for themysql.user
system table. -
The currently authenticated account has the
CREATE USER
andSYSTEM_USER
privileges.
-
-
Otherwise, the currently authenticated account can see the row for that account. Additionally, if the account has the
CREATE USER
privilege but not theSYSTEM_USER
privilege, it can see rows for all other accounts that do not have theSYSTEM_USER
privilege.
-
For more information about specifying account comments and attributes, see Section 15.7.1.3, “CREATE USER Statement”.